The invention relates to a method for descaling a metal surface of a semifinished metal product, in which the semifinished metal product is guided in the transporting direction past nozzle head parts that rotate about rotation axes and are arranged alongside one another transversely to this transporting direction, and in which high-pressure fluid jets that are directed at the metal surface are produced by means of nozzle elements arranged on these rotating nozzle head parts, said fluid jets also being blasted as far as the metal surface at a narrow point between two immediately adjacent nozzle head parts.
The invention also relates to an apparatus for carrying out a method for descaling a metal surface of a semifinished metal product, having a nozzle device, past which the semifinished metal product is guidable in the transporting direction, wherein the nozzle device has a multiplicity of nozzle head parts that rotate about the rotation axes, said nozzle head parts having nozzle elements for producing high-pressure fluid jets that are directed at the metal surface, wherein the nozzle head parts are arranged alongside one another such that the fluid jets produced by the nozzle elements are also blasted as far as the metal surface at a narrow point between two immediately adjacent nozzle head parts.
Furthermore, the invention relates to an installation for producing semifinished metal products, in particular metal strip material, having an apparatus for descaling the metal surfaces of the semifinished metal products.
In particular generic methods and apparatuses are well known from the prior art.
For example, the laid-open specification DE 43 28 303 A1 discloses a device for descaling hot rolled materials which are guided past this device. In that case, the surfaces of each rolled material are then cleaned or descaled by being blasted on both sides with high-pressure water. The descaling device proposed therein has nozzle heads arranged in a row alongside one another, which are each driven in rotation about a rotation axis by a motor. The nozzle heads have at least one eccentrically arranged nozzle, by means of which high-pressure water jets are produced and can be blasted onto the surfaces. By way of the rotationally driven nozzle heads, an improved surface quality of the blasted surfaces of the rolled material is intended to be achieved.
The international application WO 2005/082 555 A1 discloses a further device for descaling hot rolled materials, having nozzle heads arranged in a row, which are each driven in rotation about a rotation axis by a motor. The descaling device taught therein is characterized in that the nozzles arranged on the rotationally driven nozzle heads are arranged as close as structurally possible to the circumference of the particular nozzle head. In that case, a spray pattern is intended to be produced on the rolled material surface, said spray pattern at least touching the spray pattern of the adjacent nozzle head in the nozzle head row in order to achieve uniform descaling of the rolled material surface over the width thereof. Furthermore, adjacent nozzle heads in the nozzle head row are intended to rotate in opposite directions in order to avoid undesired mutual jet influencing.
Furthermore, U.S. Pat. No. 5,697,241 A describes a rolling device having a rolling stand and an upstream rotor descaling device, wherein the liquid jets emerging from the rotor descaling device and striking the rolled material are directed counter to the rolling direction. As a result, the liquid striking the rolled material surface at the striking point of the liquid jet is intended, after striking, to have a flow resultant which has a component in the opposite direction to the rolling direction such that, in spite of as little liquid application as possible, a satisfactory surface quality is achievable.
A further descaling device for descaling a semifinished metal product is disclosed in JP H11 216513 A, in which rotary heads equipped with high-pressure water nozzles are arranged not only alongside one another in the widthwise direction of the semifinished metal product but also in an offset manner with respect to one another in the conveying direction of the semifinished metal product, in order to achieve operationally reliable descaling across the entire width of the semifinished metal product. However, this descaling device has a very deep construction in the conveying direction.
JP H06 226215 A discloses a further cleaning machine having rotating nozzle heads that is movable over a surface to be cleaned, for instance a floor or the like, said rotating nozzle heads each comprising a rotor arm, wherein each of the rotor arms has two or more high-pressure nozzles, the liquid jets of which merge at a point before the surface to be cleaned, in order to achieve an improved cleaning effect. The rotor arms are arranged with respect to one another and operated such that, although they mesh with one another during rotation, they do not collide with one another.